This works somewhat like the problem of a car on an incline plane
If the track were flat then the normal force would simply be the weight.
But because of the 8 degree bank Ncos(t) = weight = 800g
N = 800*g/cos(8)
The Horizontal component N sin(t) provides the centripetal force
Nsin(8) = mv^2/R
Using your result from the first part v^2 = Nsin(8)R/m